Method for manufacturing a curved heat exchanger using wedge shaped segments

ABSTRACT

A method for manufacturing a heat exchanger includes stacking a plurality of parting sheets, a plurality of lengthwise closure bars, and a plurality of widthwise closure bars to form a rectangular first heat exchanger section. The first heat exchanger section includes at least one widthwise passage extending between a pair of the widthwise closure bars and at least one lengthwise passage extending between a pair of the lengthwise closure bars. The method also includes brazing the rectangular first heat exchanger section together and cutting a first side and a second side of the rectangular first heat exchanger section to give the first heat exchanger section a tapered-trapezoid profile. The method further includes brazing an end of a second heat exchanger section to the first or second side of the first heat exchanger section.

STATEMENT OF GOVERNMENT INTEREST

This invention was made with government support under Contract No. FA8626-16-C-2139 awarded by the United States Air Force. The government has certain rights in the invention.

BACKGROUND

The present disclosure relates to heat exchangers, and in particular to curved plate-fin heat exchangers.

Heat exchangers are often used to transfer heat between two fluids. For example, in aircraft environmental control systems, heat exchangers may be used to transfer heat between a relatively hot air source (e.g., bleed air from a gas turbine engine) and a relatively cool air source (e.g., ram air). Some heat exchangers, often referred to as plate-fin heat exchangers, include a plate-fin core having multiple heat transfer sheets arranged in layers to define air passages there between. Closure bars seal alternating inlets of hot air and cool air inlet sides of the core. Accordingly, hot air and cool air are directed through alternating passages to form alternating layers of hot and cool air within the core. Heat is transferred between the hot and cool air via the heat transfer sheets that separate the layers. In addition, to facilitate heat transfer between the layers, each of the passages can include heat transfer fins, often formed of corrugated material (e.g., aluminum), that are oriented in a direction of the flow within the passage. The heat transfer fins increase turbulence and a surface area that is exposed to the airflow, thereby enhancing heat transfer between the layers.

Due to existing corrugated sheet structures and manufacturing techniques, known plate-fin heat exchangers have a rectangular axial cross section. In some applications, such as aircraft environmental control systems, the plate-fin heat exchangers are arranged around a central axis. As a result of the rectangular cross section of the plate-fin heat exchangers, gaps occur between adjacent plate-fin heat exchangers and between a curved housing and the plate-fin heat exchangers when the plate-fin heat exchangers are arranged circumferentially about the central axis. These gaps creates dead space next to the plate-fin heat exchangers that cannot be used by the plate-fin heat exchangers.

SUMMARY

In one embodiment, a heat exchanger includes a first section with a top side opposite a bottom side, wherein the top side is longer than the bottom side. The first section also includes a first side extending between the top side and the bottom side, and a second side extending between the top side and the bottom side opposite the first side. The first side and the second side of the first section taper toward each other as the first side and the second side extend toward the bottom side of the first section. The heat exchanger also includes a second section with a top side opposite a bottom side, and a first side extending between the top side of the second section and the bottom side of the second section. The second section also includes a second side extending between the top side of the second section and the bottom side of the second section opposite the first side of the second section. The second side of the second section of the heat exchanger is connected to the first side of the first section of the heat exchanger. A header manifold is connected to the first side of the second section.

In another embodiment, a heat exchanger includes a first section with a top opposite a bottom, a lengthwise dimension transverse to a widthwise dimension, and a first parting sheet at the top of the first section. The first section also includes a first lengthwise closure bar and a second lengthwise closure bar under the first parting sheet, with the first and second lengthwise closure bars extending in the lengthwise dimension and spaced from each other in the widthwise dimension. A second parting sheet is under the first and second lengthwise closure bars. The first parting sheet, the second parting sheet, the first lengthwise closure bar, and the second lengthwise closure bar together form a first lengthwise passage that extends in the lengthwise dimension through the first section of the heat exchanger. A first widthwise closure bar and a second widthwise closure bar are under the second parting sheet. The first and second widthwise closure bars extend in the widthwise dimension and are spaced from each other in the lengthwise dimension. A third parting sheet is under the first and second widthwise closure bars. The second parting sheet, the third parting sheet, the first widthwise closure bar, and the second widthwise closure bar together form a first widthwise passage that extends in the widthwise dimension through the first section of the heat exchanger. A third lengthwise closure bar and a fourth lengthwise closure bar are under the third parting sheet and extend in the lengthwise dimension and are spaced from each other in the widthwise dimension. A fourth parting sheet is under the third and fourth lengthwise closure bars. The third parting sheet, the fourth parting sheet, the third lengthwise closure bar, and the fourth lengthwise closure bar together form a second lengthwise passage that extends in the lengthwise dimension through the first section of the heat exchanger. The first and second lengthwise closure bars of the first section are both longer than the third and fourth lengthwise closure bars of the first section.

In another embodiment, a method for manufacturing a heat exchanger includes stacking a plurality of parting sheets, a plurality of lengthwise closure bars, and a plurality of widthwise closure bars to form a rectangular first heat exchanger section. The first heat exchanger section includes at least one widthwise passage extending between a pair of the widthwise closure bars and at least one lengthwise passage extending between a pair of the lengthwise closure bars. The method also includes brazing the rectangular first heat exchanger section together and cutting a first side and a second end of the rectangular first heat exchanger section to give the first heat exchanger section a tapered-trapezoid profile. The method further includes stacking a second plurality of parting sheets, a second plurality of lengthwise closure bars, and a second plurality of widthwise closure bars to form a second heat exchanger section. The second heat exchanger section includes at least one widthwise passage extending between a pair of the second plurality of widthwise closure bars and at least one lengthwise passage extending between a pair of the second plurality of lengthwise closure bars. The method further includes brazing the second heat exchanger section together, and brazing an end of the second heat exchanger section to the first or second end of the first heat exchanger section.

Persons of ordinary skill in the art will recognize that other aspects and embodiments are possible in view of the entirety of the present disclosure, including the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a heat exchanger.

FIG. 2A is a perspective view of a section of the heat exchanger.

FIG. 2B is a side elevation view of the section of the heat exchanger from FIG. 2A.

FIG. 3A is a perspective view of a section of the heat exchanger prior to a cutting step.

FIG. 3B is a side elevation view of the section of the heat exchanger from FIG. 3A.

FIG. 4 is a side elevation view of the heat exchanger.

While the above-identified drawing figures set forth one or more embodiments, other embodiments are also contemplated. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the claims. The figures may not be drawn to scale, and applications and embodiments may include features and components not specifically shown in the drawings. Like reference numerals identify similar structural elements.

DETAILED DESCRIPTION

The disclosure relates to a heat exchanger with multiple core sections. At least one of the core sections of the heat exchanger is wedge-shaped (i.e., tapered on two sides). When the wedge-shaped core section(s) is connected to adjacent core sections in the heat exchanger, the interface between the tapered sides of the wedge-shaped core section(s) and the adjacent core sections creates a bend (or bends) in the overall geometry of the heat exchanger. The bend(s) in the heat exchanger allow the heat exchanger to curve and better fill and utilize non-rectangular spaces. The disclosure also relates to a method for manufacturing this heat exchanger. The bent heat exchanger is described below with reference to FIGS. 1-4.

FIG. 1 is a perspective view of heat exchanger 10. As shown in FIG. 1, heat exchanger 10 includes first header 12 a, second header 12 b, and core 14 with first section 14 a, second section 14 b, and third section 14 c. First header 12 a includes inlet 16 and second header 12 b includes outlet 18. First section 14 a of core 14 includes top side 20 a, bottom side 22 a, first side 24 a, and second side 26 a. Second section 14 b of core 14 includes top side 20 b, bottom side 22 b, first side 24 b, and second side 26 b. Third section 14 c of core 14 includes top side 20 c, bottom side 22 c, first side 24 c, and second side 26 c. Heat exchanger 10 also includes first bend 28 and second bend 30. Hot air F1 and cool air F2 interact with heat exchanger 10.

Top side 20 a of first section 14 a is positioned opposite bottom side 22 a. First side 24 a of first section 14 a is positioned opposite second side 26 a, and both first side 24 a and second side 26 a of first section 14 a extend from top side 20 a to bottom side 22 a. Top side 20 a is longer than bottom side 22 a, causing first side 24 a and second side 26 a to taper toward each other as they extend to bottom side 22 a. In the embodiment of FIG. 1, second section 14 b of core 14 is identical to first section 14 a, except that first side 24 b of second section 14 b is not tapered. Top side 20 b of second section 14 b is positioned opposite bottom side 22 b. First side 24 b of second section 14 b is positioned opposite second side 26 b, and both first side 24 b and second side 26 b of second section 14 b extend from top side 20 b to bottom side 22 b. Top side 20 b is longer than bottom side 22 b, second side 26 b to taper as second side 26 b extends to bottom side 22 b. In the embodiment of FIG. 1, third section 14 c of core 14 is also identical to first section 14 a, except that second side 26 c of third section 14 c is not tapered. Top side 20 c of third section 14 c is positioned opposite bottom side 22 c. First side 24 c of third section 14 c is positioned opposite second side 26 c, and both first side 24 c and second side 26 c of third section 14 c extend from top side 20 c to bottom side 22 c. Top side 20 c is longer than bottom side 22 c, causing first side 24 c to taper as first side 24 c extends to bottom side 22 c.

Third section 14 c, first section 14 a, and second section 14 b of core 14 are connected in series between first header 12 a and second header 12 b. As shown in FIG. 1, first header 12 a is connected to first side 24 b of second section 14 b. Second side 26 b of second section 14 b is connected to first side 24 a of first section 14 a. Second side 26 a of first section 14 a is connected to first side 24 c of third section 14 c. Second side 26 c of third section 14 c is connected to second header 12 b. First section 14 a, second section 14 b, and third section 14 c of core 14 are brazed together to form core 14. First header 12 a and second header 12 b are welded to core 14 to form heat exchanger 10. Because first section 14 a is tapered and portions of second section 14 b and third section 14 c are tapered, first bend 28 occurs in heat exchanger 10 between first section 14 a and second section 14 b of core 14, and second bend 30 occurs between first section 14 a and third section 14 c of core 14. First bend 28 and second bend 30 in heat exchanger 10 cause heat exchanger 10 to arc and curve from first header 12 a to second header 12 b. Because heat exchanger 10 arcs and curves from first header 12 a to second header 12 b, heat exchanger 10 can be used in curved spaces, such as curved or annular ducts in aircraft environmental control systems.

During operation of heat exchanger 10, hot air F1 enters inlet 16 on first header 12 a where first header 12 a directs hot air F1 in second section 14 b of core 14. As discussed below with respect to FIGS. 2A and 2B, heat exchanger 10 is a plate-fin heat exchanger with lengthwise passages that extend completely through second section 14 b, first section 14 a, and third section 14 c so that hot air F1 is able to flow from first header 12 a, through core 14, and into second header 12 b. After entering second header 12 b, hot air F1 exits heat exchanger 10 through outlet 18 of second header 12 b. As also discussed below with reference to FIGS. 2A and 2B, first section 14 a, second section 14 b, and third section 14 c of core 14 each include widthwise passages that allow cool air F2 to flow orthogonally through core 14 without mixing with hot air F1.

FIG. 2A is a perspective view of first section 14 a of core 14 of heat exchanger 10. FIG. 2B is a side elevation view of first section 14 a of core 14 of heat exchanger 10 from FIG. 2A. While FIGS. 2A and 2B illustrate first section 14 a of core 14, the following discussion of FIGS. 2A and 2B can be adapted and applied to second section 14 b and third section 14 c of core 14. As shown in FIGS. 2A and 2B, first section 14 a further includes parting sheets 32 a-32 j, lengthwise closure bars 34 a-34 e, widthwise closure bars 36 a-36 d, hot-gas passages 38 a-38 e, cool-gas passages 40 a-40 d, lengthwise corrugated sheets 42 a-42 e, widthwise corrugated sheets 44 a-44 d, top end sheet 46 a, and bottom end sheet 48 a.

In FIGS. 2A and 2B, a lengthwise dimension X of first section 14 a is defined as the direction parallel to the x-axis, a widthwise dimension Z of first section 14 a is defined as the direction parallel to the z-axis, and a height dimension Y of first section 14 a is defined as the direction parallel to the y-axis. To form first section 14 a, the elements of first section 14 a are stacked in the height dimension Y in the following order, descending from top side 20 a to bottom side 22 a of first section 14 a: top end sheet 46 a, parting sheet 32 a, lengthwise closure bars 34 a (two shown), lengthwise corrugation 42 a, parting sheet 32 b, widthwise closure bars 36 a (two shown), widthwise corrugation 44 a, parting sheet 32 c, lengthwise closure bars 34 b (two shown), lengthwise corrugation 42 b, parting sheet 32 d, widthwise closure bars 36 b (two shown), widthwise corrugation 44 b, parting sheet 32 e, lengthwise closure bars 34 c (two shown), lengthwise corrugation 42 c, parting sheet 32 f, widthwise closure bars 36 c (two shown), widthwise corrugation 44 c, parting sheet 32 g, lengthwise closure bars 34 d (two shown), lengthwise corrugation 42 d, parting sheet 32 h, widthwise closure bars 36 d (two shown), widthwise corrugation 44 d, parting sheet 32 i, lengthwise closure bars 34 e (two shown), lengthwise corrugation 42 e, parting sheet 32 j, and bottom end sheet 48 a.

All of lengthwise closure bars 34 a-34 e shown in FIGS. 2A and 2B extend in the lengthwise dimension X and each pair of lengthwise closure bars 34 a-34 e are spaced apart in the widthwise dimension Z. Hot-gas passages 38 a-38 e are passages that extend in the lengthwise dimension X through first section 14 a. Hot-gas passages 38 a-38 e are formed by lengthwise closure bars 34 a-34 e and parting sheets 32 a-32 j. For example, parting sheet 32 a, parting sheet 32 b, lengthwise corrugation 42 a, and lengthwise closure bars 34 a form hot-gas passage 38 a. Parting sheet 32 c, parting sheet 32 d, lengthwise corrugation 42 b, and lengthwise closure bars 34 b form hot-gas passage 38 b. Parting sheet 32 e, parting sheet 32 f, lengthwise corrugation 42 c, and lengthwise closure bars 34 c form hot-gas passage 38 c. Parting sheet 32 g, parting sheet 32 h, lengthwise corrugation 42 d, and lengthwise closure bars 34 d form hot-gas passage 38 d. Parting sheet 32 i, parting sheet 32 j, lengthwise corrugation 42 e, and lengthwise closure bars 34 e form hot-gas passage 38 e.

All of widthwise closure bars 36 a-36 d shown in FIGS. 2A and 2B extend in the widthwise dimension Z and each pair of widthwise closure bars 36 a-36 d are spaced apart in the lengthwise dimension X. Cool-gas passages 40 a-40 d are passages that extend in the widthwise dimension Z through first section 14 a. Cool-gas passages 40 a-40 d are formed by widthwise closure bars 36 a-36 d and parting sheets 32 b-32 i. For example, parting sheet 32 b, parting sheet 32 c, widthwise corrugation 44 a, and widthwise closure bars 36 a form cool-gas passage 40 a. Parting sheet 32 d, parting sheet 32 e, widthwise corrugation 44 b, and widthwise closure bars 36 b form cool-gas passage 40 b. Parting sheet 32 f, parting sheet 32 g, widthwise corrugation 44 c, and widthwise closure bars 36 c form cool-gas passage 40 c. Parting sheet 32 h, parting sheet 32 i, widthwise corrugation 44 d, and widthwise closure bars 36 d form cool-gas passage 40 d.

The configuration of first section 14 a in FIGS. 2A and 2B alternates hot-gas passages 38 a-38 e with cool-gas passages 40 a-40 d along the height dimension Y such that each one of cool-gas passages 40 a-40 d is positioned vertically on first section 14 a between two of hot-gas passages 38 a-38 e. Alternating hot-gas passages 38 a-38 e with cool-gas passages 40 a-40 d improves the efficiency of first section 14 a of heat exchanger 10 by increasing the heat transfer area between hot air F1 and cool air F2. To further increase the heat transfer area inside first section 14 a, lengthwise corrugated sheets 42 a-42 e are positioned inside hot-gas passages 38 a-38 e respectively, and widthwise corrugated sheets 44 a-44 d are positioned inside cool-gas passages 40 a-40 d respectively. Lengthwise corrugated sheets 42 a-42 e extend the entire length of hot-gas passages 38 a-38 e respectively, and widthwise corrugated sheets 44 a-44 d extend the entire length of cool-gas passages 40 a-40 d respectively.

As previously discussed above with reference to FIG. 1, first section 14 a of core 14 is tapered with top side 20 a longer than bottom side 22 a, and first side 24 a and second side 26 a tapering toward each other as they extend to bottom side 22 a of first section 14 a. FIG. 2B best illustrates the tapered profile of first section 14 a. As shown in FIG. 2B, lengthwise closure bars 34 a-34 e decrease in length in the X dimension from top side 20 a to bottom side 22 a. For example, the two lengthwise closure bars 34 a are longer in the X dimension than the two lengthwise closure bars 34 b. Lengthwise closure bars 34 e have the shortest length among lengthwise closure bars 34 a-34 e. Parting sheets 32 a-32 j also decrease in length in the X dimension from top side 20 a to bottom side 22 a. For example, parting sheet 32 a is longer than parting sheet 32 b in the X dimension, and parting sheet 32 b is longer than parting sheet 32 c in the X dimension. Parting sheet 32 j has the shortest length of parting sheets 32 a-32 j in the X dimension.

As part of forming tapered first side 24 a and second side 26 a of first section 14 a, each of widthwise closure bars 36 a-36 d includes a ramping trapezoid cross-section on the X-Y plane with two ninety-degree angles, one obtuse angle, and one acute angle. Each of lengthwise closure bars 34 a-34 e include a rectangular cross-section on the Y-Z plane and an elongated isosceles trapezoid profile on the X-Y plane. Overall, first section 14 a of core 14 (shown in FIG. 1) has a tapered-trapezoid profile on the X-Y plane with the length of first section 14 a in the X dimension decreasing from top end sheet 46 down to bottom end sheet 48. A method for manufacturing first section 14 a (as well as second section 14 b and third section 14 c) and heat exchanger 10 is described below with reference to FIGS. 3A-4.

FIG. 3A is a perspective view of a prefinished embodiment of first section 14 a of core 14 (shown in FIG. 1) for heat exchanger 10 (also shown in FIG. 1). FIG. 3B is a side elevation view of the prefinished embodiment of first section 14 a from FIG. 3A. FIG. 4 is a side elevation view of a completed embodiment of heat exchanger 10. While FIGS. 3A and 3B illustrate first section 14 a, the following discussion of FIGS. 3A and 3B can also be applied to second section 14 b and third section 14 c of core 14.

To manufacture first section 14 a, the elements of first section 14 a are stacked in the height dimension Y in the following order, descending from top side 20 a to bottom side 22 a of first section 14 a: top end sheet 46 a, parting sheet 32 a, lengthwise closure bars 34 a, parting sheet 32 b, widthwise closure bars 36 a, parting sheet 32 c, lengthwise closure bars 34 b, parting sheet 32 d, widthwise closure bars 36 b, parting sheet 32 e, lengthwise closure bars 34 c, parting sheet 32 f, widthwise closure bars 36 c, parting sheet 32 g, lengthwise closure bars 34 d, parting sheet 32 h, widthwise closure bars 36 d, parting sheet 32 i, lengthwise closure bars 34 e, parting sheet 32 j, and bottom end sheet 48 a, lengthwise corrugated sheets 42 a-42 e are inserted inside hot-gas passages 38 a-38 e respectively, and widthwise corrugated sheets 44 a-44 d are inserted inside cool-gas passages 40 a-40 d respectively.

As shown best in FIG. 3B, all of lengthwise closure bars 34 a-34 e originally have the same length in the X dimension. Widthwise closure bars 36 a-36 d have differing thicknesses in the X dimension, with the thickness of widthwise closure bars 36 a-36 d increasing from widthwise closure bars 36 a down to widthwise closure bars 36 d. For example widthwise closure bars 36 a are each thinner in the X dimension than widthwise closure bars 36 b, and widthwise closure bars 36 b are thinner in the X dimension than widthwise closure bars 36 c. Widthwise closure bars 36 d are the thickest of widthwise closure bars 36 a-36 d.

After stacking parting sheets 32 a-32 j, lengthwise closure bars 34 a-34 e, widthwise closure bars 36 a-36 d, lengthwise corrugated sheets 42 a-42 e, widthwise corrugated sheets 44 a-44 d, top end sheet 46 a, and bottom end sheet 48 a as described above, the above listed elements are brazed together into a rectangular prefinished first section 14 a using a first braze material at a first temperature. After the elements of prefinished first section 14 are brazed together, the ends of prefinished first section 14 are cut along lines L1 and L2 to form tapered first side 24 a and tapered second side 26 a and give first section 14 a a tapered-trapezoid profile. The cuts along lines L1 and L2 are accommodated by the increasing thicknesses of widthwise closure bars 36 a-36 d. The cuts along lines L1 and L2 can be performed through wire-cut electrical discharge machining (EDM). After cutting first section 14 along lines L1 and L2, the above steps used to produce tapered first section 14 a of core section 14 are repeated to produce second section 14 b (shown above in FIG. 1 and below in FIG. 4) and to produce third section 14 c (shown above in FIG. 1 and below in FIG. 4). Because first side 24 b of second section 14 b and second side 26 c of third section 14 c are both not tapered (as discussed previously with reference to FIG. 1), second section 14 b and third section 14 c each only require one angled cut.

After manufacturing first section 14 a, second section 14 b, and third section 14 c, the three sections 14 a, 14 b, and 14 c are positioned relative one another such that hot-gas passages 38 a-38 e of first section 14 a are contiguous with hot-gas passages 38 a-38 e of second section 14 b and third section 14 c respectively, as shown in FIG. 4. First section 14 a, second section 14 b, and third section 14 c are then brazed together to form core 14 using a second braze material at a second temperature. The second braze material has a lower melting temperature than the first braze material, and thus the second temperature is lower than the first temperature. Because first section 14 a, second section 14 b, and third section 14 c are brazed at a lower temperature than the first brazing temperature used to produce sections 14 a, 14 b, and 14 c, first section 14 a, second section 14 b, and/or third section 14 c are not at risk of individually falling apart during the second braze. First header 12 a and second header 12 b are then positioned relative core 14 and welded to core 14.

As shown in FIG. 4, first header manifold 12 a is welded to first side 24 b of second section 14 b. Second side 26 b of second section 14 b is connected by the second braze material to first side 24 a of first section 14 b. Second side 26 a of first section 14 a is connected by the second braze material to first side 24 c of third section 14 c. Second side 26 c of third section 14 c is welded to second header 12 b. Because of the tapered sides of first section 14 a, second section 14 b, and third section 14 c, first bend 28 and second bend 30 are formed in core 14 of heat exchanger 10. First bend 28 and second bend 30 in heat exchanger 10 cause heat exchanger 10 to arc and curve from first header 12 a to second header 12 b. Because heat exchanger 10 arcs and curves from first header 12 a to second header 12 b, heat exchanger 10 can be used in curved spaces, such as curved or annular ducts in aircraft environmental control systems.

The following are non-exclusive descriptions of possible embodiments of the present invention.

In one embodiment, a heat exchanger includes a first section with a top side opposite a bottom side, wherein the top side is longer than the bottom side. The first section also includes a first side extending between the top side and the bottom side, and a second side extending between the top side and the bottom side opposite the first side. The first side and the second side of the first section taper toward each other as the first side and the second side extend toward the bottom side of the first section. The heat exchanger also includes a second section with a top side opposite a bottom side, and a first side extending between the top side of the second section and the bottom side of the second section. The second section also includes a second side extending between the top side of the second section and the bottom side of the second section opposite the first side of the second section. The second side of the second section of the heat exchanger is connected to the first side of the first section of the heat exchanger. A header manifold is connected to the first side of the second section.

The heat exchanger of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:

the top side of the second section is longer than the bottom side of the second section, and the first side of the second section and/or the second side of the second section taper from the top side of the second section to the bottom side of the second section;

a first hot-gas passage extending from the first side of the first section to the second side of the first section; and a second hot-gas passage extending from the first side of the second section to the second side of the second section, wherein the second hot-gas passage of the second section is contiguous with the first hot-gas passage of the first section; and/or

a first corrugated sheet inside the first hot-gas passage of the first section and extending from the first side of the first section to the second side of the first section; and a second corrugated sheet inside the second hot-gas passage of the second section and extending from the first side of the second section to the second side of the second section.

In another embodiment, a heat exchanger includes a first section with a top opposite a bottom, a lengthwise dimension transverse to a widthwise dimension, and a first parting sheet at the top of the first section. The first section also includes a first lengthwise closure bar and a second lengthwise closure bar under the first parting sheet, with the first and second lengthwise closure bars extending in the lengthwise dimension and spaced from each other in the widthwise dimension. A second parting sheet is under the first and second lengthwise closure bars. The first parting sheet, the second parting sheet, the first lengthwise closure bar, and the second lengthwise closure bar together form a first lengthwise passage that extends in the lengthwise dimension through the first section of the heat exchanger. A first widthwise closure bar and a second widthwise closure bar are under the second parting sheet. The first and second widthwise closure bars extend in the widthwise dimension and are spaced from each other in the lengthwise dimension. A third parting sheet is under the first and second widthwise closure bars. The second parting sheet, the third parting sheet, the first widthwise closure bar, and the second widthwise closure bar together form a first widthwise passage that extends in the widthwise dimension through the first section of the heat exchanger. A third lengthwise closure bar and a fourth lengthwise closure bar are under the third parting sheet and extend in the lengthwise dimension and are spaced from each other in the widthwise dimension. A fourth parting sheet is under the third and fourth lengthwise closure bars. The third parting sheet, the fourth parting sheet, the third lengthwise closure bar, and the fourth lengthwise closure bar together form a second lengthwise passage that extends in the lengthwise dimension through the first section of the heat exchanger. The first and second lengthwise closure bars of the first section are both longer than the third and fourth lengthwise closure bars of the first section.

The heat exchanger of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:

the length of the first section tapers from the first parting sheet to the fourth parting sheet;

the first section further comprises: a third widthwise closure bar and a fourth widthwise closure bar under the fourth parting sheet, wherein the third and fourth widthwise closure bars extend in the widthwise dimension and are spaced from each other in the lengthwise dimension; and a fifth parting sheet under the third and fourth widthwise closure bars, wherein the fourth parting sheet, the fifth parting sheet, the third widthwise closure bar, and the fourth widthwise closure bar together form a second widthwise passage that extends in the widthwise dimension through the first section of the heat exchanger;

a second section comprising: a top, a bottom, a lengthwise dimension, a widthwise dimension, a first parting sheet, a second parting sheet, a third parting sheet, a fourth parting sheet, a first lengthwise closure bar, a second lengthwise closure bar, a third lengthwise closure bar, a fourth lengthwise closure bar, a first widthwise closure bar, a second widthwise closure bar, a first lengthwise passage, a second lengthwise passage, and a first widthwise passage all arranged in the same manner as the first section of the heat exchanger, wherein the first widthwise closure bar of the second section of the heat exchanger is connected to the second widthwise closure bar of the first section of the heat exchanger, wherein the first lengthwise passage of the second section of the heat exchanger is contiguous with the first lengthwise passage of the first section of the heat exchanger, and wherein the second lengthwise passage of the second section of the heat exchanger is contiguous with the second lengthwise passage of the first section of the heat exchanger;

the first parting sheet of the first section is longer than the second parting sheet of the first section, wherein the second parting sheet of the first section is longer than the third parting sheet of the first section, wherein the third parting sheet of the first section is longer than the fourth parting sheet of the first section;

a first corrugated sheet inside the first lengthwise passage of the first section of the heat exchanger; a second corrugated sheet inside the second lengthwise passage of the first section of the heat exchanger; a third corrugated sheet inside the first widthwise passage of the first section of the heat exchanger; a fourth corrugated sheet inside the first lengthwise passage of the second section of the heat exchanger; a fifth corrugated sheet inside the second lengthwise passage of the second section of the heat exchanger; and a sixth corrugated sheet inside the first widthwise passage of the second section of the heat exchanger;

a first braze material connects together at least the following parts of the first section: the first parting sheet, the second parting sheet, the third parting sheet, the fourth parting sheet, the first lengthwise closure bar, the second lengthwise closure bar, the third lengthwise closure bar, the fourth lengthwise closure bar, the first widthwise closure bar, and the second widthwise closure bar;

a second braze material connects the first section of the heat exchanger to the second section of the heat exchanger, wherein the second braze material has a lower melting temperature than the first braze material; and/or

a header manifold is welded to the second widthwise closure bar of the second section or the first widthwise closure bar of the first section.

In another embodiment, a method for manufacturing a heat exchanger includes stacking a plurality of parting sheets, a plurality of lengthwise closure bars, and a plurality of widthwise closure bars to form a rectangular first heat exchanger section. The first heat exchanger section includes at least one widthwise passage extending between a pair of the widthwise closure bars and at least one lengthwise passage extending between a pair of the lengthwise closure bars. The method also includes brazing the rectangular first heat exchanger section together and cutting a first side and a second side of the rectangular first heat exchanger section to give the first heat exchanger section a tapered-trapezoid profile. The method further includes stacking a second plurality of parting sheets, a second plurality of lengthwise closure bars, and a second plurality of widthwise closure bars to form a second heat exchanger section. The second heat exchanger section includes at least one widthwise passage extending between a pair of the second plurality of widthwise closure bars and at least one lengthwise passage extending between a pair of the second plurality of lengthwise closure bars. The method further includes brazing the second heat exchanger section together, and brazing an end of the second heat exchanger section to the first or second side of the first heat exchanger section.

The method of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:

brazing the rectangular first heat exchanger section together at a first temperature; brazing the second heat exchanger section together at the first temperature; and brazing the end of the second heat exchanger section to the first or second side of the first heat exchanger section at a second temperature, wherein the second temperature is lower than the first temperature;

the plurality of widthwise closure bars of the first heat exchanger section prior to cutting comprises a first pair of widthwise closure bars and a second pair of widthwise closure bars, wherein the widthwise closure bars in the first pair are each thicker than the widthwise closure bars in the second pair;

brazing the end of the second heat exchanger section to the first side of the first heat exchanger section; and welding a header manifold to the second heat exchanger section opposite the first heat exchanger section;

brazing the second heat exchanger section together; cutting a first side and/or a second side of the second heat exchanger section to taper the first side and/or second side of the second heat exchanger section; brazing the second side of the second heat exchanger section to the first side of the first heat exchanger section;

brazing the second heat exchanger section to the first heat exchanger section forms a bend in the heat exchanger; and/or

stacking a third plurality of parting sheets, a third plurality of lengthwise closure bars, and a third plurality of widthwise closure bars to form a third heat exchanger section with at least one widthwise passage extending between a pair of the third plurality of widthwise closure bars and at least one lengthwise passage extending between a pair of the third plurality of lengthwise closure bars; cutting a first side and/or a second side of the third heat exchanger section to taper the first side and/or second side of the third heat exchanger section; and brazing the first side of the third heat exchanger section to the second side of the first heat exchanger section, wherein brazing the third heat exchanger section to the first heat exchanger section forms a second bend in the heat exchanger.

Any relative terms or terms of degree used herein, such as “substantially”, “essentially”, “generally”, “approximately”, and the like, should be interpreted in accordance with and subject to any applicable definitions or limits expressly stated herein. In all instances, any relative terms or terms of degree used herein should be interpreted to broadly encompass any relevant disclosed embodiments as well as such ranges or variations as would be understood by a person of ordinary skill in the art in view of the entirety of the present disclosure, such as to encompass ordinary manufacturing tolerance variations, incidental alignment variations, transitory vibrations and sway movements, temporary alignment or shape variations induced by operational conditions, and the like.

While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. For example, while the above disclosure describes core 14 as having three sections 14 a, 14 b, and 14 c, core 14 of heat exchanger 10 can have more than three sections. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. For example, while the above disclosure describes first section 14 a, second section 14 b, and third section 14 c as being the same as one another, core 14 can include non-identical sections. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims. 

The invention claimed is:
 1. A heat exchanger comprising: a first section comprising: a top side opposite a bottom side, wherein the top side is longer than the bottom side; a first side extending between the top side and the bottom side; and a second side extending between the top side and the bottom side opposite the first side, wherein the first side and the second side taper toward each other as the first side and the second side extend toward the bottom side; a second section comprising: a top side opposite a bottom side; a first side extending between the top side of the second section and the bottom side of the second section; and a second side extending between the top side of the second section and the bottom side of the second section opposite the first side of the second section, wherein the second side of the second section is connected to the first side of the first; a first hot-gas passage extending from the first side of the first section to the second side of the first section; and a second hot-gas passage extending from the first side of the second section to the second side of the second section, wherein the second hot-gas passage of the second section is contiguous with the first hot-gas passage of the first section; and a header manifold connected to the first side of the second section.
 2. The heat exchanger of claim 1, wherein the top side of the second section is longer than the bottom side of the second section, and the first side of the second section and/or the second side of the second section taper from the top side of the second section to the bottom side of the second section.
 3. The heat exchanger of claim 1, wherein the heat exchanger further comprises: a first corrugated sheet inside the first hot-gas passage of the first section and extending from the first side of the first section to the second side of the first section; and a second corrugated sheet inside the second hot-gas passage of the second section and extending from the first side of the second section to the second side of the second section.
 4. A heat exchanger comprising: a first section comprising: a top opposite a bottom; a lengthwise dimension transverse to a widthwise dimension; a first parting sheet at the top of the first section; a first lengthwise closure bar and a second lengthwise closure bar under the first parting sheet, wherein the first and second lengthwise closure bars extend in the lengthwise dimension and are spaced from each other in the widthwise dimension; a second parting sheet under the first and second lengthwise closure bars, wherein the first parting sheet, the second parting sheet, the first lengthwise closure bar, and the second lengthwise closure bar together form a first lengthwise passage that extends in the lengthwise dimension through the first section of the heat exchanger; a first widthwise closure bar and a second widthwise closure bar under the second parting sheet, wherein the first and second widthwise closure bars extend in the widthwise dimension and are spaced from each other in the lengthwise dimension; a third parting sheet under the first and second widthwise closure bars, wherein the second parting sheet, the third parting sheet, the first widthwise closure bar, and the second widthwise closure bar together form a first widthwise passage that extends in the widthwise dimension through the first section of the heat exchanger; a third lengthwise closure bar and a fourth lengthwise closure bar under the third parting sheet, wherein the third and fourth lengthwise closure bars extend in the lengthwise dimension and are spaced from each other in the widthwise dimension; and a fourth parting sheet under the third and fourth lengthwise closure bars, wherein the third parting sheet, the fourth parting sheet, the third lengthwise closure bar, and the fourth lengthwise closure bar together form a second lengthwise passage that extends in the lengthwise dimension through the first section of the heat exchanger, wherein the first and second lengthwise closure bars are both longer than the third and fourth lengthwise closure bars.
 5. The heat exchanger of claim 4, wherein the length of the first section tapers from the first parting sheet to the fourth parting sheet.
 6. The heat exchanger of claim 5, wherein the first section further comprises: a third widthwise closure bar and a fourth widthwise closure bar under the fourth parting sheet, wherein the third and fourth widthwise closure bars extend in the widthwise dimension and are spaced from each other in the lengthwise dimension; and a fifth parting sheet under the third and fourth widthwise closure bars, wherein the fourth parting sheet, the fifth parting sheet, the third widthwise closure bar, and the fourth widthwise closure bar together form a second widthwise passage that extends in the widthwise dimension through the first section of the heat exchanger.
 7. The heat exchanger of claim 4 further comprising: a second section comprising: a top, a bottom, a lengthwise dimension, a widthwise dimension, a first parting sheet, a second parting sheet, a third parting sheet, a fourth parting sheet, a first lengthwise closure bar, a second lengthwise closure bar, a third lengthwise closure bar, a fourth lengthwise closure bar, a first widthwise closure bar, a second widthwise closure bar, a first lengthwise passage, a second lengthwise passage, and a first widthwise passage all arranged in the same manner as the first section of the heat exchanger, wherein the first widthwise closure bar of the second section of the heat exchanger is connected to the second widthwise closure bar of the first section of the heat exchanger, wherein the first lengthwise passage of the second section of the heat exchanger is contiguous with the first lengthwise passage of the first section of the heat exchanger, and wherein the second lengthwise passage of the second section of the heat exchanger is contiguous with the second lengthwise passage of the first section of the heat exchanger.
 8. The heat exchanger of claim 7, wherein the first parting sheet of the first section is longer than the second parting sheet of the first section, wherein the second parting sheet of the first section is longer than the third parting sheet of the first section, wherein the third parting sheet of the first section is longer than the fourth parting sheet of the first section.
 9. The heat exchanger of claim 8 further comprising: a first corrugated sheet inside the first lengthwise passage of the first section of the heat exchanger; a second corrugated sheet inside the second lengthwise passage of the first section of the heat exchanger; a third corrugated sheet inside the first widthwise passage of the first section of the heat exchanger; a fourth corrugated sheet inside the first lengthwise passage of the second section of the heat exchanger; a fifth corrugated sheet inside the second lengthwise passage of the second section of the heat exchanger; and a sixth corrugated sheet inside the first widthwise passage of the second section of the heat exchanger.
 10. The heat exchanger of claim 8, wherein a first braze material connects together at least the following parts of the first section: the first parting sheet, the second parting sheet, the third parting sheet, the fourth parting sheet, the first lengthwise closure bar, the second lengthwise closure bar, the third lengthwise closure bar, the fourth lengthwise closure bar, the first widthwise closure bar, and the second widthwise closure bar.
 11. The heat exchanger of claim 10, wherein a second braze material connects the first section of the heat exchanger to the second section of the heat exchanger, wherein the second braze material has a lower melting temperature than the first braze material.
 12. The heat exchanger of claim 11, wherein a header manifold is welded to the second widthwise closure bar of the second section or the first widthwise closure bar of the first section.
 13. The heat exchanger of claim 6, wherein the first and third widthwise closure bars are identical to one another and the second and fourth closure bars are identical to one another. 